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United States Patent |
5,248,207
|
Yamamoto
,   et al.
|
September 28, 1993
|
Thermal printer provided with detachable head unit having built-in
thermal head unit
Abstract
A thermal printer has detachably attached to a frame assembly of a printer
a print unit having a built-in thermal head. The print unit accommodates
therein an inked ribbon. By a drive member installed within the frame
assembly, the thermal head is pressed against the platen roller and
consequently driven thereby. The print unit is provided with a unit case
and a cover allowed to be opened or shut relative to the unit case. The
inked ribbon can be attached to or detached from the interior of the unit
case. The unit is capable of incorporating the platen roller therein. In
this case, the opening of the cover induces formation of an opening
between the platen roller and the thermal head. The unit incorporating the
platen roller therein is not required to be provided in the frame assembly
thereof with the drive member which would cause the thermal head to be
pressed against the platen roller by virtue of a spring member and and
consequently induce a displacement of the thermal head. The use of a roll
of thermosensitive recording paper in the unit obviates the necessity for
the inked ribbon.
Inventors:
|
Yamamoto; Junichi (Osaka, JP);
Maeda; Yutaka (Osaka, JP)
|
Assignee:
|
Minolta Camera Kabushiki Kaisha (Osaka, JP)
|
Appl. No.:
|
750117 |
Filed:
|
August 26, 1991 |
Foreign Application Priority Data
| Aug 27, 1990[JP] | 2-224717 |
| Aug 27, 1990[JP] | 2-224718 |
Current U.S. Class: |
400/120.16; 400/208; 400/613; 400/692; 400/693.1 |
Intern'l Class: |
B41J 002/325./32/00; B41J 029/02 |
Field of Search: |
400/120,208,613,692,693,693.1
346/76 PH,145
|
References Cited
U.S. Patent Documents
4641980 | Feb., 1987 | Matsumoto et al. | 400/693.
|
4949097 | Aug., 1990 | Imaseki | 346/76.
|
5020926 | Jun., 1991 | Wilhelm | 400/693.
|
5044801 | Sep., 1991 | Uchimura et al. | 400/692.
|
Foreign Patent Documents |
49972 | Mar., 1985 | JP | 400/120.
|
116477 | Jun., 1985 | JP | 400/208.
|
61-68275 | Apr., 1986 | JP.
| |
68276 | Apr., 1986 | JP | 400/692.
|
83077 | Apr., 1986 | JP | 400/208.
|
213184 | Sep., 1986 | JP | 400/692.
|
256675 | Nov., 1987 | JP | 400/692.
|
297159 | Dec., 1987 | JP | 400/208.
|
63-188153 | Dec., 1988 | JP.
| |
Other References
IBM Technical Disclosure Bulletin, "Cassette Containing Both Ribbon and
Print Head", vol. 23 No. 9, Feb. 1981.
|
Primary Examiner: Burr; Edgar S.
Assistant Examiner: Funk; Stephen R.
Attorney, Agent or Firm: Willian Brinks Olds Hofer Gilson & Lione
Claims
What is claimed is:
1. A thermal printer possessing a platen roller and a thermal head adapted
to be pressed against said platen roller through the medium of a recording
paper and recording an image on said recording paper, comprising:
a recording medium;
a print unit for displaceably retaining and accommodating said thermal head
and for accommodating said recording medium;
a thermal printer main body;
means for attaching or detaching said print unit to said thermal printer
main body; and
pressing means installed in said thermal printer main body, and adapted to
remain in said thermal printer main body when said print unit is detached
from said thermal printer main body, for pressing said thermal head
against said platen roller when said print unit is attached to said
thermal printer main body.
2. A thermal printer according to claim 1, which further comprises
connectors adapted to electrify the thermal head in said print unit and
disposed correspondingly in said print unit and said thermal printer main
body.
3. A thermal printer according to claim 1, which further comprises a slide
base, and means for inserting said slide base into or removing said slide
base from said thermal printer main body, said slide base having said
print unit and a cassette for containing a recording paper separately
mounted thereon and removable therefrom when said slide base is removed
from said printer main body, and wherein said recording medium comprises
an inked ribbon.
4. A thermal printer according to claim 1, wherein said print unit further
includes means for containing said recording paper.
5. A thermal printer according to claim 1, wherein said recording medium
comprises an inked ribbon.
6. A thermal printer according to claim 1, wherein said recording medium
comprises a thermosensitive recording paper.
7. A thermal printer possessing a platen roller and a thermal head adapted
to be pressed against said platen roller through the medium of a recording
paper and recording an image on said recording paper, comprising:
a recording medium;
a print unit for rotatably retaining and accommodating said platen roller,
for displaceably retaining and accommodating said thermal head, and for
accommodating said recording medium,
a thermal printer main body; and
means for attaching or detaching said print unit to said thermal printer
main body,
wherein said platen roller is rotatably retained by a first portion of said
print unit and said thermal head is retained by a second portion of said
print unit, wherein said print unit includes means for separating said
first and second portions for forming an opening between said platen
roller and said thermal head when said print unit is in a position
detached from said thermal printer main body, and wherein the printer main
body is provided therein with pressing means for pressing said thermal
head against said platen roller.
8. A thermal printer possessing a platen roller and a thermal head adapted
to be pressed against said platen roller through the medium of a recording
paper and recording an image on said recording paper, comprising:
a recording medium;
a print unit for rotatably retaining and accommodating said platen roller,
for displaceably retaining and accommodating said thermal head, and for
accommodating said recording medium,
a thermal printer main body; and
means for attaching or detaching said print unit to said thermal printer
main body,
wherein said platen roller is rotatably retained by a first portion of said
print unit and said thermal head is retained by a second portion of said
print unit, wherein said print unit includes means for separating said
first and second portions for forming an opening between said platen
roller and said thermal head when said print unit is in a position
detached from said thermal printer main body, and wherein said recording
medium comprises an inked ribbon.
9. A thermal printer according to claim 8, wherein said print unit further
includes means for detachably accommodating therein a roll of recording
paper on which a print is formed by the use of said thermal head and said
inked ribbon.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a thermal printer which is provided with a platen
roller and a thermal head pressed against the platen roller through the
medium of a recording paper and is adapted to form an image on the
recording paper.
2. Description of the Related Art
A thermal printer is possessed of a thermal head which is pressed against a
platen roller through the medium of a recording paper. The thermal printer
comes in two types; the one type using a recording medium in the form of
an inked ribbon or inked film and forming an image on the recording paper
by transferring the ink applied on this ribbon onto the recording paper
and the other type using a recording medium in the form of a
thermosensitive paper by directly forming an image on a thermosensitive
paper without using any inked ribbon.
The thermal printer of this construction is characterized by having a
relatively small size and operating at a low cost as compared with other
systems for recording an image on a recording paper. The conventional
thermal printer, however, is limited in miniaturization because it
requires to secure an exchange space for allowing attachment and
detachment of an ink ribbon to and from a frame assembly or printer body
and an escape space for allowing retraction of the thermal head during the
exchange of the ink ribbon. Further, the conventional thermal printer has
unsolved problems concerning further reduction in production cost,
reduction in weight, improvement in operability, facilitation of
maintenance such as of the thermal head, facilitation of exchange of
consumable supplies such as a recording paper and an inked ribbon,
facilitation of troubleshooting, and so on.
Japanese Patent Laid-Open 61-68,275, for example, discloses a printer which
has an inked film, a thermal head, and a switch drive mechanism for
driving the thermal head accommodated in a unit case adapted to be
attached to and detached from a printer frame. In this printer, the
operator's manual operation of the switch drive mechanism causes the unit
case to be attached to or detached from the printer frame and, at the same
time, causes the thermal head to be pressed against or moved away from a
platen roller disposed inside the printer frame. In this printer, however,
since the aforementioned switch drive mechanism for causing the thermal
head to be pressed against or moved away from the platen roller is
disposed inside the unit case, the unit case is voluminous, heavy,
expensive, and irksome in the work of attachment and detachment. Further,
the exchange of consumable supplies and the work of troubleshooting are
not easy. Thus, this printer has problems concerning reduction in size,
reduction in cost, reduction in weight, improvement in operability, etc.
The idea of inserting or removing the inked ribbon into or from the
printer through the upper side of the printer frame or in the direction of
the axis of rotation of the platen roller has been materialized for the
purpose of precluding the work of retracting the thermal head during the
insertion or removal of the inked ribbon and obviating the necessity for
allocating an extra escape space to the retraction. This device, however,
has a problem of poor operability because the operation for inserting or
removing the inked ribbon into or from the printer frame cannot be carried
out on the front side of the printer frame.
SUMMARY OF THE INVENTION
An object of this invention is to provide a thermal printer which allows
further reduction in size, weight, and cost and, at the same time, excels
in operability owing to facilitation of the work of exchange of consumable
supplies and the work of troubleshooting.
Another object of this invention is to provide a thermal printer which
allows attachment to or detachment from the printer frame a print unit
having a thermal head and an inked ribbon recording medium built therein.
Yet another object of this invention is to provide a thermal printer which
allows attachment to or detachment from the printer frame a print unit
having a thermal head, a platen roller, and an inked ribbon built therein.
Still another object of this invention is to provide a thermal printer
which allows attachment to or detachment from the printer frame a print
unit having a thermal head, a platen roller, an inked ribbon, and a
recording paper built therein.
A further object of this invention is to provide a thermal printer which
allows attachment to or detachment from the printer frame a print unit
having a thermal head and a thermosensitive recording paper recording
medium built therein.
A still further object of this invention is to provide a thermal printer
which allows attachment to or detachment from the printer frame a print
unit having a thermal head, a platen roller, and a thermosensitive
recording paper built therein.
In accordance with the present invention, there is provided a thermal
printer possessing a platen roller and a thermal head adapted to be
pressed against said platen roller through the medium of a recording paper
and recording an image on said recording paper by heating said recording
paper, comprising a print unit for displaceably retaining and
accommodating therein said thermal head, accommodating an inked ribbon
therein, and allowing itself to be attached to or detached from said
thermal printer body and pressing means installed in said thermal printer
body and adapted to press said thermal head against said platen roller.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross section illustrating a thermal printer as the first
embodiment of this invention in a position having a print unit and a
paper-feeding cassette disposed inside a printer frame;
FIG. 2 is a cross section illustrating the thermal printer shown in FIG. 1
in a position performing the work of printing;
FIG. 3 is a cross section illustrating the thermal printer in process of
removal of the print unit;
FIG. 4 is a cross section illustrating the thermal printer in a position
resulting from the removal of the print unit;
FIG. 5 is a cross section illustrating the print unit shown in FIGS. 1 to
4;
FIG. 6 is a cross section illustrating the print unit in a position
allowing insertion of the inked ribbon through an opening formed by an
upper cover;
FIG. 7 is a perspective view illustrating the outward appearance of the
print unit;
FIG. 8 is a cross section illustrating a thermal printer as the second
embodiment of this invention;
FIG. 9 is a cross section illustrating a thermal printer as the third
embodiment of this invention;
FIG. 10 is a cross section illustrating a thermal printer as the fourth
embodiment of this invention;
FIG. 11 is a cross section illustrating the print unit shown in FIG. 10;
FIG. 12 is a cross section illustrating the print unit shown in FIG. 11 in
a position having the upper cover opened;
FIG. 13 is a cross section illustrating a print unit as the fifth
embodiment of this invention;
FIG. 14 is a cross section illustrating the print unit of FIG. 13 in a
position having the lower cover opened;
FIG. 15 is a cross section illustrating a thermal printer as the sixth
embodiment of this invention;
FIG. 16 is a cross section illustrating a print unit built in the thermal
printer of FIG. 15;
FIG. 17 is a cross section illustrating a thermal printer as the seventh
embodiment of this invention;
FIG. 18 is a cross section illustrating the print unit shown in FIG. 17;
FIG. 19 is a cross section illustrating the print unit shown in FIG. 18 in
a position having the upper cover opened;
FIG. 20 is a cross section illustrating a print unit as the eighth
embodiment of this invention;
FIG. 21 is a cross section illustrating the print unit shown in FIG. 20 in
a position having the upper cover opened;
FIG. 22 is a cross section illustrating a print unit as the ninth
embodiment of this invention;
FIG. 23 is a cross section illustrating the print unit shown in FIG. 22 in
a position having the upper cover opened.
FIG. 24 is a cross section illustrating a print unit as the tenth
embodiment of this invention;
FIG. 25 is a cross section illustrating the print unit of FIG. 24 in a
position having the upper cover opened.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A thermal printer 1 shown in FIGS. 1 to 4 is provided with a platen roller
2, and a thermal head 3 pressed as heated against the thermal head 3
through the medium of a recording paper P and an inked film or inked
ribbon R as a recording medium. On the recording paper P, an image is
formed with the ink from the ink ribbon R thermally transferred. The
illustrated platen roller 2 is disposed rotatably in both directions
inside the main body of the thermal printer 1 or a frame assembly 4. On a
guide plate 5 provided in the lower part of the frame assembly 4, a moving
tray 6 is mounted so as to be moved in both ways in the longitudinal
direction in the bearings of the diagram. On the moving tray 6, a
paper-moving cassette 7 is mounted on the right side and a print unit 8 on
the left side in the bearings of the diagram. These components are adapted
to be incorporated in the frame assembly 4 mentioned above.
A pin 10 is attached to a bracket which is disposed substantially in the
middle of the lower part of the frame assembly 4 and the basal terminal
part of a paper-feeding lever 9 is attached to this pin 10 and the leading
terminal part of the paper-feeding lever 9 is adapted to be moved
vertically. This paper-feeding lever 9 is vertically moved by a drive
member (not shown). On the bottom wall of the paper-feeding cassette 7, a
pressure plate 11 is seated so as to be vertically moved. When the
paper-feeding lever 9 is set driving, it is raised through openings formed
in the bottom walls respectively of the guide plate 5, the moving tray 6,
and the paper-feeding cassette 7 and pressed against the pressure plate
11. Inside the paper-feeding cassette 7, a multiplicity of sheetlike
recording papers P are accommodated as piled up on the pressure plate 11.
A paper-feeding roller 12 held in contact with the uppermost of these
recording papers is disposed above the paper-feeding lever 9 inside the
frame assembly 4. This paper-feeding roller 12 is rotationally driven in
the clockwise direction in the bearings of the diagram.
Inside the frame assembly 4, a guide 13 for guiding the recording papers P
is attached as interposed between the paper-feeding roller 12 and the
platen roller 2 and paper-retaining rollers 14 adapted to be pressed
upwardly against the platen roller 12 by virtue of a spring (not shown)
are disposed. These paper-retaining rollers 14 are so disposed as to be
pressed against the platen roller 12 through the medium of the lateral
part of the recording papers P and prevented from interfering with the
print unit 8. A conveying path 16 for discharging used recording papers P
out of the printer is defined by upper and lower guides 15a, 15b which are
fixed inside the frame assembly 4. The upper guide 15a is provided with a
paper sensor 17 adapted to detect the leading end of a recording paper P
being conveyed.
To a pin 19 which is attached through the medium of the bracket to the
lower part of the front terminal part of the frame assembly 4, a drive
lever 18 is attached by the basal terminal part thereof. The leading
terminal part of this drive lever 18 is adapted to be moved vertically by
a drive member (not shown). This drive lever 18 constitutes itself a drive
mechanism for causing the thermal head 3 disposed inside a unit case 20 of
the print unit 8 to be pressed against the platen roller 2 or removed from
the platen roller 2 and moved away therefrom and, therefore, corresponds
to a drive mechanism for the conventional printer described above. When
this drive lever 18 is driven upwardly, it presses an operating member 21
attached to the thermal head 3 through openings formed in the guide plate
5, the moving tray 6, and the unit case 20 at the positions corresponding
to the position of the drive lever 18. As a result, the drive lever 18
presses the thermal head 3 against the platen roller 2 through the medium
of the inked ribbon R and the recording paper P as illustrated in FIG. 2.
A control part 22 is provided for the frame assembly 4. This control part
22 is connected through the medium of a cable to a connector 23 which is
attached downwardly protrudingly to the lower side of the moving tray 6.
To the unit case 20, a connector 24 projected from the lower side thereof
is attached. This connector 24 is connected to the thermal head 3 through
the medium of a cable. When the print unit 8 is moved and mounted on the
moving tray 7, the connector 24 is fitted into a through hole formed in
the moving tray 7 and brought into contact with the connector 23. As a
result, the thermal head 3 is electrically connected to the control part
22. From the control part 22, an electric energy is supplied and, at the
same time, such electric signals of data, clock, latch, and strobe which
have been introduced as from an external computer and processed by the
control part 22 are transmitted to the thermal head 3.
This printer 1 has the front side at the left terminal part of the frame
assembly 4 in the bearings of the diagram. It has an open part 25 formed
in the front side part. While the printer 1 is in a position having the
moving tray 6 drawn out past the open part 25 in the direction of
conveyance of the recording papers P as illustrated in FIG. 3, the
attachment and detachment of the print unit 8 and the paper-feeding
cassette 7 into and out of the moving tray 6 are carried out. When the
moving tray 6 in a position having the print unit 8 and the paper-feeding
cassette 7 incorporated in place therein is driven into place, the print
unit 8 and the paper-feeding cassette 7 are set at their prescribed
positions inside the frame assembly 4. A slit 5a for allowing passage of
the connector 23 during the movement of the moving tray 6 is formed in the
guide plate 5. To allow the moving tray 6 smooth movement, a guide
projection 6a is extended from the lower side of the tray 6 in the
direction of movement thereof. This guide projection 6a is meshed with a
slit (not shown) formed in the guide plate 5.
FIGS. 5 to 7 illustrate the print unit 8. This print unit 8 is provided
with the unit case 20 mentioned above and an upper cover 26 adapted to be
opened and shut with a pin 27 relative to the unit case 20. Inside the
unit case 20, the inked ribbon R which is wound on a supply reel 28 and
rewound on a take-up reel 29 is detachably accommodated. The thermal head
3 is set on a supporting shaft 30 inside the unit case 20 so as to be
shaken around the supporting shaft 30.
The inked ribbon R is formed by applying a pigment type thermally meltable
or dye type thermally sublimable solid ink on a base film. Where a color
image is to be printed, for example, an inked film having solid inks of
the three colors, i.e. yellow, magenta, and cyan, applied severally in a
fixed length repeatedly in the order mentioned is used. On the thermal
head 3, a multiplicity of heating elements are rectilinearly arrayed.
These elements are selectively heated by electrification. This heating is
carried out on the basis of data emitted severally relative to the three
colors by the control part 22.
The operating member 21 is provided with a basal terminal part 21a and a
peel part 21b rising perpendicularly relative thereto and is possessed of
a cross section substantially of the shape of the letter L. This operating
member 21 fulfills not only the function of transmitting the pressing
force of the drive lever 18 through the medium of a spring 31 to the
thermal head 3 and pressing the thermal head 3 against the platen roller 2
but also the function of peeling the inked ribbon R from the recording
paper P which has passed the gap between the thermal head 3 and the platen
roller 2 as illustrated in FIG. 2. The spring 31 is interposed between the
thermal head 3 and the basal terminal part 21a of the operating member 21
and adapted to effect adjustment of the pressing force exerted by the
thermal head 3 on the platen roller 2.
As illustrated in FIG. 7, the unit case 20 has two supporting shafts 32, 33
set in place. These supporting shafts are each provided with a plurality
of engaging pieces 34 possessed of a projection at the leading end
thereof. The supporting shafts 32, 33 are inserted into the unit case 20
severally through supporting holes 38 formed in the unit case 20 and the
engaging pieces 34 are inserted into the core part of the take-up reel 29.
The core part of the supply reel 28 is supported in place by semicircular
supporting parts 39 projected inwardly from the unit case 20. The
supporting shaft 32 is provided with a toothed wheel 35 and the toothed
wheel 35 is meshed with a drive toothed wheel (not shown) disposed inside
the frame assembly 4. By a motor which drives the drive toothed wheel, the
take-up reel 29 inside the print unit 8 is rotated and the inked ribbon R
is conveyed as unwound from the supply reel 28 and rewound on the take-up
reel 29. Optionally, the supporting shafts 32, 33 and the toothed wheel 35
may be fixed integrally with the take-up reel 29.
The unit case 20 is provided at the leading end thereof with a handle 36 as
illustrated in FIG. 7. An opening 37 is formed in the upper cover 26.
Through the medium of this opening 37, the thermal head 3 inside the print
unit 8 is pressed against the platen roller 2. By the platen roller 2, the
recording paper P and the inked ribbon R are conveyed.
The illustrated print unit 8 is provided with the unit case 20 on the lower
side and the upper cover 26 adapted to be opened and shut relative
thereto. Optionally, the upper cover 26 and the unit case 20 may be
integrally formed so as to give rise to a tightly closed unit case. In
this case, the print unit 8 inclusive of the thermal head 3, the inked
ribbon R, the supply reel 28, and the take-up reel 29 accommodated therein
forms a disposable item.
Now, the procedure for printing an image on the recording paper P by
thermally transferring the ink from the inked ribbon R by the use of the
thermal printer 1 described above will be explained below.
When a print-starting switch (not shown) is depressed, the paper-feeding
lever 9 is raised as indicated by a two-dot chain line and, at the same
time, the paper-feeding roller 12 is rotationally driven as illustrated in
FIG. 2. As a result, just one of the recording papers P is sent out of the
paper-feeding cassette 7 toward the left in the bearings of FIG. 2. The
recording paper P thus sent out passes the gap between the guide 13 and
the cover 26 of the print unit 8 and reaches the gap between the platen
roller 2 and the paper-retaining roller 14 pressed against the platen
roller 2. After the leading end of the recording paper P collides against
and fits into the nipping part between the platen roller 2 and the
paper-retaining roller 14, the recording paper P is conveyed by the
rotation of the platen roller 2. During the conveyance, the paper-feeding
lever 9 is returned to a lowered position as indicated by a solid line in
FIG. 2.
When the recording paper P is conveyed to the position at which the leading
end thereof is detected by the paper sensor 17, the drive lever 18 is
moved upwardly as illustrated in FIG. 2 and the thermal head 2 is pressed
against the platen roller 2 across the recording paper P and the inked
ribbon R through the medium of the operating member 21 and the spring 31.
In this state, the printing by thermal transfer is started. FIG. 2
illustrates the state in which the printing is in process. This printing
is effected by the fact that the multiplicity of heating elements provided
on the thermal head 2 are selectively heated by electrification based on
the data emitted from the control part 22 and consequently the ink from
the inked ribbon R is thermally transferred onto the recording paper P.
The recording paper P and the inked ribbon R are conveyed by the rotation
as of the platen roller 2, with the result that the recording paper P is
brought to the conveying path 16 and the inked ribbon R is rewound on the
take-up reel 29.
To print a color image on the recording paper P, the recording paper P is
returned over a prescribed distance by the reversing of the platen roller
2 and the paper-retaining roller 14 after the drive lever 18 is returned
to the lowered position indicated in FIG. 1 subsequently to the completion
of the first printing operation. Then, the drive lever 18 is again raised
and the thermal head 3 is pressed against the platen roller 2 to effect
the printing operation in the second color. The printing operation in the
third color and possibly the printing operation in the fourth color are
carried out in the same manner as described above. When the last printing
operation is completed, the recording paper P is conveyed by the platen
roller 2 and the paper-retaining roller 14 and discharged through the
conveying path 16 and the drive lever 18 is returned to the lowered
position.
In the thermal printer 1, the thermal head 3, the inked ribbon R, etc. are
built in the print unit 8 which is adapted to be attached to and detached
from the frame assembly 4 as described above and the thermal head 3 is
displaced by the drive lever 18 on the printer's frame assembly 4 side.
The thermal head 3 inside the print unit 8 is adapted to be electrically
connected to the control part 22 through the medium of the connectors 23,
24. The thermal printer described above has the following advantages.
The drive lever 18 is provided for the frame assembly 4 and not for the
printer unit 8. Since the print unit 8 of the present thermal printer is
not provided with a drive member for pressing the thermal head 3 against
the platen roller 2, it is allowed a reduction in size and weight.
Optionally, the print unit 8 may be designed as a disposable item. Since
the frame assembly 4 is not required to be provided with an exchange space
for allowing insertion and removal of the inked ribbon R or with an escape
space or escape mechanism for allowing retraction of the thermal head 3
during the exchange the printer is allowed a decrease in height and a
further reduction in size, weight, and cost.
The printer has its front surface on the left side in the bearings of FIGS.
1 to 4. Since the attachment or detachment of the print unit 8 to or from
the printer is accomplished by inserting or removing the moving tray 6
through the opening part 25, the efficiency of the operation of attaching
or detaching the print unit 8 to or from the printer is improved.
Particularly, since the print unit 8 is allowed a reduction in weight, the
printer enjoys ideal efficiency in the operation of attachment and
detachment.
The work of maintenance of the print unit 8 is facilitated by the fact that
the print unit 8 can be removed from the moving tray 6 coupled with the
fact that the drive lever 18 is not attached to the print unit 8. By
removing the print unit 8 from the frame assembly 4 of the printer, the
exchange of such consumable supplies as recording paper P and inked ribbon
R can be accomplished easily. The troubleshooting such as the removal of a
recording paper P stuck in the mechanism may be easily attained with the
print unit 8 in a position drawn out of the frame assembly 4. From the
position illustrated in FIG. 1, the moving tray 6 is drawn out past the
front side of the printer to the position illustrated in FIG. 3. Then, the
print unit 8 is taken out of the moving tray 6 as illustrated in FIG. 4.
The paper-feeding cassette 7, when necessary, may be moved on the moving
tray 6 in the direction of the front side of the printer. To exchange the
inked ribbon R for a new supply, the cover 26 of the print unit 8 is
opened as illustrated in FIG. 6. As a result, the exchange of the thermal
head 3, the exchange of the inked ribbon R, the loading of the recording
paper P, and the removal of a stuck recording paper can be easily carried
out. After these works are completed, the print unit 8 is returned to the
prescribed position inside the printer as illustrated in FIG. 1 by
reversing the procedure described above.
Though the thermal printer 1 described above is so constructed that the
moving tray 6 will be moved in the direction of conveyance of the
recording paper, the printer of the present invention does not
discriminate the moving tray 6 on account of the direction of its
movement.
A thermal printer 1a illustrated in FIG. 8 is so constructed that the
moving tray 6 is allowed to move in the direction perpendicular to the
surface of the drawing. When the moving tray 6 is moved, therefore, the
print unit 8 and the paper-feeding cassette 7 during the removal or
insertion are moved in the direction parallel to the axis of rotation of
the platen roller 2. This printer 1a has its front side on the nearer side
in the bearings of FIG. 8. During the removal or insertion of the moving
tray 6, the guide projection 6a is slid as guided by the slit formed in
the guide plate 5. Similarly, a thermal printer 1b illustrated in FIG. 9
is allowed to move in the direction perpendicular to the surface of the
drawing.
In the lateral part of the thermal printer 1a illustrated in FIG. 8, the
frame assembly 4 is provided with a paper discharge part 40 for receiving
and holding used recording papers P which are discharged via the conveying
path 16. In this case, the recording papers P after use are discharged to
the left side of the printer. In the printer 1b illustrated in FIG. 9, the
paper discharge part 40 for storing used recording papers P is formed on
the upper side of the printer 1b. Into this paper discharge part 40, the
used recording papers P are discharged via the conveying path 16 which has
a curved shape. This invention allows the direction of discharge of the
used recording papers to be selected in various directions.
In the printers 1a, 1b illustrated respectively in FIG. 8 and FIG. 9 and in
printers of other types to be described hereinbelow, the component members
identical with those of the thermal printer of the first embodiment
illustrated in FIGS. 1 to 7 are denoted by identical reference numerals.
FIGS. 10 to 12 represent a thermal printer 1c as the fourth embodiment of
this invention. In this printer 1c, the platen roller 2 is also built in
the print unit 8a. Inside the unit case 20, the thermal head 3 is set so
as to be shaken around the pin 30 and, at the same time, the
paper-retaining roller 14 is rotatably set in place as illustrated. In the
upper cover 26, the platen roller 2 adapted to be pressed against the
thermal head across the recording paper P and the inked ribbon R is
rotatably set in place. The paper-retaining roller 14 is urged by the
resilient force exerted by the spring (not shown) in the direction of the
platen roller 2.
When the upper cover 26 is opened with the print unit 8a in a position
removed from the frame assembly 4 of the printer as illustrated in FIG.
12, the platen roller 2 is separated from the thermal head 3 to allow
exchange of the inked ribbon R.
The upper cover 26 is provided on the laterally opposite sides of the
platen roller 2 with upper guide members 41, 43, on the right side of the
platen roller 2 with a lower guide member 42, and on the left side thereof
with a lower guide member 44. The upper guide member 41 and the lower
guide member 44 jointly define a conveying inclined toward the inlet side
and the upper guide member 43 and the lower guide member 44 jointly define
a conveying path 46 inclined toward the outlet side. These conveying paths
45, 46 open outside the print unit 8a. In the unit cases 20, depressed
parts 47 corresponding to the upper guide members 41, 43 are formed as
illustrated in FIG. 12. When the upper cover 26 is in a shut state as
illustrated in FIG. 10 and FIG. 11, the upper cover 26 comes into contact
with the depressed part 47 and, as a result, the upper cover 26, the
platen roller 2, the paper-retaining roller 14, etc. are set in place.
The print unit 8a of the thermal printer 1c is not provided with either of
the operating member 21 and the spring 31 which are used in the print unit
8 of the thermal head 1 illustrated in FIG. 1. The thermal head 3 is
directly depressed by the drive lever 18. The function of fine adjustment
to be fulfilled by the spring 31 is accomplished by the adjustment of the
position of the upper limit of the reach of the drive lever 18. To the
thermal head 3, a peel member 48 adapted to peel the inked ribbon R from
the recording paper P is attached.
To the frame assembly 4 of the thermal printer 1c, a guide 50 is attached
as extended in the horizontal direction so as to cover the entire upper
surface of the print unit 8a as illustrated in FIG. 10. The right side
part of the guide 50 defines a conveying path 51 and the left side part
thereof defines a conveying path 52 respectively in conjunction with the
upper cover 26. The conveying path 51 communicates with the conveying path
45 and the conveying path 52 with the conveying path 46. The central part
of the guide 50 collides against the upper surface of the upper cover 26
of the print unit and exerts slight pressing force on the upper cover 26
and consequently sets the print unit 8a in place. This guide 50 guides the
print unit 8a during the removal or insertion of the moving tray 6 and
smoothens the work of loading of the print unit 8a in the printer 1c.
In this printer 1c, the recording paper P is forwarded from the
paper-feeding cassette 7 through the conveying paths 51, 45, then passed
through the gap between the platen roller 2 and the thermal head 3 and the
paper-retaining roller 14, further passed through the conveying paths 46,
52, and finally discharged out of the printer. This printer 1c, like the
printer 1, has the front surface thereof on the left side in the bearings
of the drawing. The moving tray 6 is drawn out through the opening part
25.
FIG. 13 and FIG. 14 illustrate a printer unit 8b of another type to be
loaded in the printer 1c illustrated in FIG. 10. This print unit 8b is
provided on the lower side of the unit case 20 with the lower cover 26
which is set so as to be opened and shut around the pin 27 as the center.
This print unit 8b, therefore, is opened on the lower side thereof. In
this case, the platen roller 2 is attached to the unit case 20 on the
upper side and the inked ribbon R which is unwound from the supply reel 28
and rewound on the take-up reel 29 is accommodated in the unit case 20. To
the lower cover 26, the thermal head 3 is attached as enabled to be shaken
around the pin through the medium of a bracket 53 which is formed
integrally with the lower cover 26. The connector 24 is attached to the
lower side of the lower cover 26. In the unit case 20, a notched part 54
is formed at the position corresponding to that of the bracket 53. When
the lower cover 20 is shut, therefore, the bracket 53 collides against the
notched part 54 and consequently sets the lower cover 26, the thermal head
3, etc. in place. In the print unit 8b of this type, the unit case 20 and
the lower cover 26 may be integrally formed and used as a tightly closed
item. In this case, the print unit 8b accommodating therein the platen
roller 2, the thermal head 3, the inked ribbon R, etc. constitutes itself
a disposable item.
The print units 8a, 8b described above are adapted so as to incorporate
therein not only the thermal head but also the platen roller 2. When they
are in a position taken out of the printer 1c, the platen roller 2 and the
thermal head 3 are separated from each other. The thermal printer 1C which
is possessed of the print unit 8a or 8b of this type enjoys the following
advantages in addition to those of the thermal printer 1 of the first
embodiment of this invention.
This printer, unlike the conventional printer, obviates the necessity for
providing inside the frame assembly 4 an exchange space for allowing the
insertion or removal of the inked ribbon R and an escape space or escape
mechanism for allowing retraction of the thermal head during the exchange
and allows a decrease in the height of the printer and a further reduction
in size, weight, and cost.
Since the platen roller 2 is incorporated in the print unit 8a or 8b, the
printer is allowed a further reduction in size as clearly noted from the
comparison of FIG. 1 and FIG. 10. Further since the platen roller 2 as
well as the component members like the thermal head 3 and the inked ribbon
R is incorporated in the print unit 8a or 8b, the positional accuracy of
the platen roller 2 and the thermal head 3 is high, the production and
assembly of the printer are easy, and the cost of production of the
printer is low.
Further, the print unit 8a or 8b can be attached or detached through the
front side of the printer by the insertion or removal of the moving tray 6
through the opening part 25 on the front side of the printer. Thus, the
work of the attachment or detachment is carried out with high efficiency.
Since the print unit 8a or 8b has the inked ribbon R and the platen roller
2 incorporated therein, the inked ribbon R has no possibility of colliding
against the platen roller 2 and has only remote possibility of sustaining
damage during the insertion or removal of the print unit 8a or 8b into or
from the printer. Also from this point of view, the print unit 8a or 8b
enjoys high efficiency of the work of attachment or detachment.
After the removal of the print unit 8b from the printer, the opening of the
lower cover 26 induces separation between the platen roller 2 and the
thermal head 3 and consequently facilitates the maintenance of the platen
roller 2 and the thermal head 3. Similarly, the extraction of the print
unit 8a contributes to facilitating the exchange of such consumable
supplies as the recording paper P and the inked ribbon R. Further, the
extraction of the print unit 8a serves the purpose of facilitating the
work of troubleshooting which is required as when the recording paper P is
stuck in the mechanism.
FIG. 15 and FIG. 16 illustrate a thermal printer 1d as yet another
embodiment of this invention. The basic construction of this printer 1d is
identical with that of the printer 1c illustrated in FIG. 10, except the
thermal head 3 incorporated in the print unit 8c is constantly kept
pressed against the platen roller 2 by a spring 55 attached to the unit
case 20. This thermal printer 1d, therefore, is not provided in the frame
assembly 4 thereof with the drive lever 18 described above. To the thermal
head 3 is attached a projection 56. A stopper 57 adapted to be united with
this projection 56 is attached to the unit case 20. As a result, when the
cover 26 of the print unit 8 is opened, the platen roller 2 is separated
from the thermal head 3 but the rotation of the thermal head 3 around the
pin 30 as the center beyond a prescribed magnitude is restricted by the
stopper 57.
The thermal printer 1d illustrated in FIG. 15 has no use for the drive
member otherwise required for making or breaking contact between the
thermal head 3 and the platen roller 2, for the thermal head 3 is
constantly kept pressed against the platen roller 2. This fact brings
about an advantage that the thermal printer is allowed a further reduction
in size and cost of production. Particularly, this thermal printer 1d is
useful not only for printing color images but also for printing
monochromic images. Also in the print unit 8c of this type, the lower
cover 26 may be attached to the unit case 20 so as to be opened or shut as
desired.
FIG. 17 is a diagram illustrating a printer 1e of still another type. A
print unit 8d to be incorporated in this printer 1e is illustrated in FIG.
18 and FIG. 19.
This print unit 8d is so adapted as to accommodate therein a rolled
recording paper Pa in addition to the thermal head 3 and the inked ribbon
R. A paper roll 60 having the recording paper Pa wound in a roll is
accommodated contiguosly to the supply reel 28 in the unit case 20. In the
process of printing, the recording paper Pa is unwound from the paper roll
60, guided to the lower side of the upper cover 26, and then conveyed in
the direction of the platen roller 2 installed in the frame assembly 4.
This printer 1e is not provided with any of the paper-feeding cassette 7,
the paper-feeding roller 12, and similar component parts used in the
aforementioned printer.
This thermal printer 1e has the following advantages in addition to the
advantages enjoyed by the printers described above. Since the recording
paper Pa is adapted to be incorporated in the print unit 8d, the printer
is allowed a further reduction in size. Since the paper roll 60 is taken
out of the printer in conjunction with the print unit 8d, the exchange of
the recording paper Pa as well as that of the inked ribbon R can be easily
carried out. Thus, the troubles such as are caused when the recording
paper Pa is stuck in the mechanism can be easily coped with.
FIG. 20 and FIG. 21 illustrate a print unit 8e of another type which is
adapted to accommodate therein the recording paper. The inked ribbon R and
the recording paper P are detachably accommodated in the unit case 20 to
which the thermal head 3 is attached as adapted to rotate around the pin
30. To the upper cover 26, similarly to that illustrated in FIG. 10, the
platen roller 2 is rotatably added. This thermal head 3, as illustrated in
FIG. 10, is driven to be displaced by the drive lever installed in the
frame assembly 4.
FIG. 22 and FIG. 23 illustrate a print unit 8f as yet another embodiment of
this invention. This print unit 8f is so adapted as to accommodate therein
a roll 61 of thermosensitive paper Pb as a recording medium. Since the
thermosensitive paper Pb is used as the recording medium, this print unit
8f has no use for the inked ribbon R which is used in each of the print
units described above. This thermal head 3 is adapted to be pressed
against the platen roller (not shown) disposed in the printer's frame
assembly. This thermal head 3, similarly to that of the printer
illustrated in FIG. 1, is driven to be displaced by the drive lever.
FIG. 24 and FIG. 25 illustrate a print unit 8g of yet another type using a
thermosensitive paper Pb as a recording medium. This print unit 8g,
similarly to the countertype illustrated in FIG. 22 and FIG. 23, is
adapted to accommodate therein the roll 61 of thermosensitive paper Pb.
The cover 26 has rotatably attached thereto the platen roller 2 against
which is pressed the thermal head 3. Similarly to the print head 8c
illustrated in FIG. 16, the pressing force which the thermal head 3
exerted on the platen roller 2 is enhanced by the spring 55. The stopper
57 for engagement with the projection 56 attached to the thermal head 3 is
formed inside the unit case 20 and enabled to restrict the position of
rotation of the thermal head 3. Thus, no drive lever is installed in the
frame assembly of the printer which is furnished with the unit 8g of this
type.
While this invention has been illustrated and described in accordance with
a preferred embodiment, it is recognized that variations and changes may
be made and equivalents employed herein without departing from the
invention as set forth in the claims.
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